The St. Louis - Cape Girardeau CCOP is a consortium of six hospitals in two separate bi-state health service areas in Eastern Missouri and Western Illinois. The investigators from the St. Louis Metropolitan area are affiliated with one or more of the five hospitals in the consortium and have worked together for the past 10 years in cancer treatment research protocols and more recently, in cancer control research studies. The Cape Girardeau investigators have worked with the CCOP for the past four years and are affiliated with the two hospitals in that city. During the next five years, we expect to accrue at least 80 credits per year for cancer treatment research protocols of the NSABP and SWOG and at least 100 credits (new participants and followup) per year for cancer control and prevention studies. These cancer control credits will be derived primarily from our participation in the Breast Cancer Prevention Trial and the Prostate Cancer Prevention Trial. We will continue to provide high quality data to the Southwest Oncology Group and the National Surgical Adjuvant Breast Program which are our research bases, utilizing the data management system developed during the past six years. In summary, we will continue our excellent performance of the past 10 years in the cancer treatment research arena and utilize our expertise in cancer control research studies as well. The past experience and abilities of the investigators and data managers provides a strong base for continuing development of this Community Clinical Oncology Program.